With the development of tumor radiology and material science, radiotherapy has gradually entered the age of “three precisions” comprising precise positioning, precise planning and precise therapy as an important means for treating cancers. When the rotating plane of a main frame is set to be perpendicular to the horizontal plane, the rotating plane is an X plane, its rotating axis at the moment is defined as a Z axis, the horizontal straight line perpendicular to and cross with the Z axis is an X axis, and the straight line perpendicular to and cross with the Z axis and the X axis respectively is a Y axis. The Z axis and the Y axis define a Y plane, the Y axis and the X axis define an X plane, and the Z axis and the X axis define a horizontal plane (Z plane). The present medical linear accelerator (radiotherapy equipment) is driven by rotation of the main frame to rotate in the X plane or a plane parallel to the X plane, the accelerator follows the main frame to rotate, and the central axis of rays emitted by the accelerator is perpendicular to the rotating axis of the main frame and is intersected with the rotating axis at a point, i.e., an isocenter. Generally, during therapy, the lesion of a patient is put at the isocenter, the main frame is rotated, the accelerator rotates around the lesion in the X plane or the plane parallel to the X plane, and thus rays irradiate the lesion from different directions to better kill sick cells.
Generally, because the position of the lesion is changed with respiration of the patient and the therapeutic condition needs to be known in time, the lesion needs to be positioned before therapy and tracked and detected during therapy. In the past, the patients need to lie on different devices, e.g., the lesion is detected and positioned on an accelerator device having low energy level, then treated on an accelerator device having high energy level, and finally detected on the accelerator device having low energy level to observe the therapeutic effect. In order to solve the problems of low efficiency, poor detection timeliness and the like of said technical solution, two technical solutions have been disclosed at present: I, a homologous dual-beam solution, e.g., Publication No. CN104188679A, the invention relates to a homologous dual-beam medical accelerator, comprising an electron gun, wherein the electron gun is connected with an accelerating tube, the accelerating tube is connected with a coupler, the coupler is connected with a waveguide through a waveguide window, the waveguide is connected with a microwave power source, the microwave power source is connected with a modulator, three energy switches are arranged on the accelerating tube, the three energy switches are respectively located among three accelerating cavities in the accelerating tube, each energy switch comprises an edge coupling cavity and a detuning rod located in the edge coupling cavity, and a movable target is arranged at the outlet end of the accelerator; by controlling the output power of the microwave power source through the modulator and simultaneously adjusting the lengths of the three detuning rods in the edge coupling cavities, energy obtained by electrons emitted by the electron gun in the accelerating tube is adjusted, KeV-level rays and MeV-level rays are thereby obtained, the homologous coaxiality of imaging and therapy is guaranteed, and the healing effect on patients is improved. However, in this solution, the accelerating tube control system is substantially complex, poor in stability and difficult in commercial application. II, a dual-source system, i.e., a KV-level accelerator is integrated to the existing MV-level accelerator system, so that the system simultaneously has two different levels of rays, but also has the problems of high manufacturing cost, heavy structure and the like.